Bird Projects

Eastern Loggerhead Shrike Program

Eastern loggerhead shrikes are one of Canada’s most endangered songbirds. In the past, they could be found from Manitoba to New Brunswick. Now, however, there are fewer than 25 breeding pairs, restricted to two small isolated pockets in Ontario: the plains of Carden and Napanee.

After a precipitous drop in the wild eastern loggerhead shrike population in the 1990s, Environment Canada invited Wildlife Preservation Canada to lead the multi-partner recovery effort in 2003. Since then, the wild population size has fluctuated. Studies have shown that although the recovery effort has prevented the species from disappearing from Canada, more work is required to identify and address the causes of the species’ decline.

The cornerstone of our shrike program is breeding birds and releasing their young to boost the wild population. Within just a few years of launching our field breeding program, we saw one of the released birds successfully migrate and return to breed with a wild shrike. This achievement was a first for a migratory songbird conservation breeding effort and brought international acclaim to the program. Since then, we’ve seen many birds returning to Ontario, often breeding and contributing more young birds to the wild population.

We house these shrikes in large enclosures situated out in the field. This exposes the young to natural habitat, including predators and prey, and allows them to develop a full range of survival skills. As part of our soft-release technique, we continue to provide some food after the young are released. Wildlife Preservation Canada coordinates the conservation breeding and release program, which includes several partners that provide breeding and overwintering facilities. Currently we release young in the Napanee and Carden plains, to supplement existing wild populations in these two core areas.

Population monitoring

We track the number of shrikes in the wild through habitat surveys, nest monitoring and colour-banding, giving us insights into return rates, population size, movements between core areas and the success of the breeding and release program. We couldn’t do this without the help of our Adopt-A-Site survey volunteers. If you’d like to become involved, contact us.

Habitat stewardship

The shortgrass habitat that shrikes need is found mainly on private land. For many years, we have worked with landowners to protect and enhance shrike habitat on their property, ensuring that shrikes have suitable nesting sites and hunting grounds.

Our research has identified the habitat features that shrikes need: from the nest tree, territory and habitat patch to landscape-level requirements. In addition, we are investigating nest predation to identify which species are the biggest threat and how habitat plays a role. The results from our ongoing research are used to improve our practices and stewardship guidelines for shrike, and we share this knowledge widely.

Identifying migratory routes and wintering grounds

Although little is known about shrike migration and wintering behaviour, it appears that the biggest causes behind the decline of this species are occurring outside Canada.

That’s why we are working with U.S. conservation partners and applying the latest tracking technologies to learn where eastern loggerhead shrikes spend the winter and what routes they take to get there. With this information in hand, we can then work with our U.S. partners to identify and confront threats during migration and overwintering to reverse declines.

The shrike recovery program has seen a number of successes to date. We are learning more about the threats to the wild population, and thousands of acres of habitat have been restored or improved.

Since 2003, the conservation breeding program has released over 1,000 young birds in Ontario!

Not only are many of these birds returning the following spring, some are returning year after year. In 2012, for example, a six-year-old female released in 2006 returned to pair with a wild male — solid evidence that the field breeding and release techniques are working.

Up to 23 per cent of shrikes spotted in the wild have been birds released from our conservation breeding program in previous years. The majority of these birds pair successfully with wild mates and contribute a significant number of young to the wild population.

Meanwhile, we continue to gather clues about where our Ontario birds go during the winter, and how they get there. So far, we have evidence that a portion of Ontario eastern loggerhead shrikes winter in both the north- and south-eastern United States, and there is a clear link with the Virginias, with birds banded in Ontario seen in Virginia, and vice versa. Tracking data has so far revealed two potential migratory strategies in Ontario, with some birds heading southwest to pass in to the U.S. around Windsor, and others appearing to head more directly south to hop across Lake Ontario. As more tracking data comes in, we’ll be able to build a clearer picture of shrike migration.

We have proven that we can breed and release shrikes that survive in the wild, migrate south and return to Ontario to breed successfully. And they do this at a rate at least as high as their wild-born counterparts. According to population viability analyses conducted in 2009 and 2015, conservation breeding alone is unlikely to restore the wild population to a self-sustaining level. However, the release of young birds has certainly had a stabilizing effect and the situation would be even worse without the breeding effort. The graph below shows the number of birds that have been found in the wild in the two main core areas, Carden and Napanee, since Wildlife Preservation Canada took over program coordination.

Releases were happening in Carden over this time, and though there were some dips in the population in that area, there were generally more birds found there than in Napanee, which didn’t host a release site until 2012. Though it’s difficult to attribute the recent upturn in the population across Ontario to any one factor, the release of juveniles has certainly had a positive effect on the numbers of birds we’ve seen in the wild, as birds coming from the conservation breeding program have made up approximately 20-30% of the wild population in recent years.

So far, the conservation breeding program is doing its job: keeping eastern loggerhead shrike present in Canada while we work to discover and address the causes of loss during the migration cycle. Once we address those causes, the conservation breeding will be an essential tool in helping the wild population begin to grow again.

The techniques we have developed can also be applied beyond eastern loggerhead shrikes. An external review of the conservation breeding program in 2008 suggested that it would ultimately provide a model for future recovery programs for other shrikes in North America and — even more broadly — for other migratory songbirds at risk.

Recovery Action

Hazel Wheeler began working at Wildlife Preservation Canada in 2013 as our shrike field biologist in the Carden area. In 2014, she took on the role of Lead Biologist, coordinating the Eastern Loggerhead Shrike Recovery Program in Ontario.
Hazel holds an Honours Bachelor of Science in Wildlife Biology from the University of Guelph and a Master’s degree in Environmental and Life Sciences from Trent University, where she looked at the importance of different habitat types as foraging areas for threatened chimney swifts.
Before joining Wildlife Preservation Canada, she helped develop national monitoring programs for avian species-at-risk, implemented and coordinated provincial volunteer-based monitoring programs and directed field teams in monitoring and research activities on several sensitive species. She is currently a member of the City of Guelph’s Environmental Advisory Committee, where she applies her conservation experience to prospective developments within the city.

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About Us

Wildlife Preservation Canada saves animals on the brink of extinction. Since 1985, we’ve been saving critically endangered species – species whose numbers in the wild are so low that a great deal more than habitat protection is required to recover them.